Merge from rustc

6 files changed, 103 insertions, 113 deletions

diff --git a/compiler/rustc_codegen_ssa/src/back/link.rs b/compiler/rustc_codegen_ssa/src/back/link.rs
index 000b2748e4f..b32865a0518 100644
--- a/compiler/rustc_codegen_ssa/src/back/link.rs
+++ b/compiler/rustc_codegen_ssa/src/back/link.rs
@@ -4,7 +4,7 @@ use rustc_data_structures::fx::FxHashSet;
 use rustc_data_structures::fx::FxIndexMap;
 use rustc_data_structures::memmap::Mmap;
 use rustc_data_structures::temp_dir::MaybeTempDir;
-use rustc_errors::{ErrorGuaranteed, Handler};
+use rustc_errors::{DiagCtxt, ErrorGuaranteed};
 use rustc_fs_util::{fix_windows_verbatim_for_gcc, try_canonicalize};
 use rustc_hir::def_id::{CrateNum, LOCAL_CRATE};
 use rustc_metadata::find_native_static_library;
@@ -52,10 +52,10 @@ use std::path::{Path, PathBuf};
 use std::process::{ExitStatus, Output, Stdio};
 use std::{env, fmt, fs, io, mem, str};
 
-pub fn ensure_removed(diag_handler: &Handler, path: &Path) {
+pub fn ensure_removed(dcx: &DiagCtxt, path: &Path) {
     if let Err(e) = fs::remove_file(path) {
         if e.kind() != io::ErrorKind::NotFound {
-            diag_handler.err(format!("failed to remove {}: {}", path.display(), e));
+            dcx.err(format!("failed to remove {}: {}", path.display(), e));
         }
     }
 }
@@ -143,7 +143,7 @@ pub fn link_binary<'a>(
                 }
             }
             if sess.opts.json_artifact_notifications {
-                sess.diagnostic().emit_artifact_notification(&out_filename, "link");
+                sess.dcx().emit_artifact_notification(&out_filename, "link");
             }
 
             if sess.prof.enabled() {
@@ -183,13 +183,13 @@ pub fn link_binary<'a>(
             |preserve_objects: bool, preserve_dwarf_objects: bool, module: &CompiledModule| {
                 if !preserve_objects {
                     if let Some(ref obj) = module.object {
-                        ensure_removed(sess.diagnostic(), obj);
+                        ensure_removed(sess.dcx(), obj);
                     }
                 }
 
                 if !preserve_dwarf_objects {
                     if let Some(ref dwo_obj) = module.dwarf_object {
-                        ensure_removed(sess.diagnostic(), dwo_obj);
+                        ensure_removed(sess.dcx(), dwo_obj);
                     }
                 }
             };
@@ -208,7 +208,7 @@ pub fn link_binary<'a>(
 
         // Remove the temporary files if output goes to stdout
         for temp in tempfiles_for_stdout_output {
-            ensure_removed(sess.diagnostic(), &temp);
+            ensure_removed(sess.dcx(), &temp);
         }
 
         // If no requested outputs require linking, then the object temporaries should
@@ -933,7 +933,7 @@ fn link_natively<'a>(
                     command: &cmd,
                     escaped_output,
                 };
-                sess.diagnostic().emit_err(err);
+                sess.dcx().emit_err(err);
                 // If MSVC's `link.exe` was expected but the return code
                 // is not a Microsoft LNK error then suggest a way to fix or
                 // install the Visual Studio build tools.
diff --git a/compiler/rustc_codegen_ssa/src/back/metadata.rs b/compiler/rustc_codegen_ssa/src/back/metadata.rs
index bc0e3a82806..b683e1b45a8 100644
--- a/compiler/rustc_codegen_ssa/src/back/metadata.rs
+++ b/compiler/rustc_codegen_ssa/src/back/metadata.rs
@@ -158,12 +158,13 @@ pub(super) fn get_metadata_xcoff<'a>(path: &Path, data: &'a [u8]) -> Result<&'a
         file.symbols().find(|sym| sym.name() == Ok(AIX_METADATA_SYMBOL_NAME))
     {
         let offset = metadata_symbol.address() as usize;
-        if offset < 8 {
+        // The offset specifies the location of rustc metadata in the .info section of XCOFF.
+        // Each string stored in .info section of XCOFF is preceded by a 4-byte length field.
+        if offset < 4 {
             return Err(format!("Invalid metadata symbol offset: {offset}"));
         }
-        // The offset specifies the location of rustc metadata in the comment section.
-        // The metadata is preceded by a 8-byte length field.
-        let len = u64::from_le_bytes(info_data[(offset - 8)..offset].try_into().unwrap()) as usize;
+        // XCOFF format uses big-endian byte order.
+        let len = u32::from_be_bytes(info_data[(offset - 4)..offset].try_into().unwrap()) as usize;
         if offset + len > (info_data.len() as usize) {
             return Err(format!(
                 "Metadata at offset {offset} with size {len} is beyond .info section"
@@ -478,9 +479,12 @@ pub fn create_wrapper_file(
             file.add_section(Vec::new(), b".text".to_vec(), SectionKind::Text);
             file.section_mut(section).flags =
                 SectionFlags::Xcoff { s_flags: xcoff::STYP_INFO as u32 };
-
-            let len = data.len() as u64;
-            let offset = file.append_section_data(section, &len.to_le_bytes(), 1);
+            // Encode string stored in .info section of XCOFF.
+            // FIXME: The length of data here is not guaranteed to fit in a u32.
+            // We may have to split the data into multiple pieces in order to
+            // store in .info section.
+            let len: u32 = data.len().try_into().unwrap();
+            let offset = file.append_section_data(section, &len.to_be_bytes(), 1);
             // Add a symbol referring to the data in .info section.
             file.add_symbol(Symbol {
                 name: AIX_METADATA_SYMBOL_NAME.into(),
@@ -599,12 +603,12 @@ pub fn create_compressed_metadata_file_for_xcoff(
         section: SymbolSection::Section(data_section),
         flags: SymbolFlags::None,
     });
-    let len = data.len() as u64;
-    let offset = file.append_section_data(section, &len.to_le_bytes(), 1);
+    let len: u32 = data.len().try_into().unwrap();
+    let offset = file.append_section_data(section, &len.to_be_bytes(), 1);
     // Add a symbol referring to the rustc metadata.
     file.add_symbol(Symbol {
         name: AIX_METADATA_SYMBOL_NAME.into(),
-        value: offset + 8, // The metadata is preceded by a 8-byte length field.
+        value: offset + 4, // The metadata is preceded by a 4-byte length field.
         size: 0,
         kind: SymbolKind::Unknown,
         scope: SymbolScope::Dynamic,
diff --git a/compiler/rustc_codegen_ssa/src/back/write.rs b/compiler/rustc_codegen_ssa/src/back/write.rs
index 40fd8c5c1d6..0442bef8a44 100644
--- a/compiler/rustc_codegen_ssa/src/back/write.rs
+++ b/compiler/rustc_codegen_ssa/src/back/write.rs
@@ -14,7 +14,7 @@ use rustc_data_structures::memmap::Mmap;
 use rustc_data_structures::profiling::{SelfProfilerRef, VerboseTimingGuard};
 use rustc_data_structures::sync::Lrc;
 use rustc_errors::emitter::Emitter;
-use rustc_errors::{translation::Translate, DiagnosticId, FatalError, Handler, Level};
+use rustc_errors::{translation::Translate, DiagCtxt, DiagnosticId, FatalError, Level};
 use rustc_errors::{DiagnosticMessage, Style};
 use rustc_fs_util::link_or_copy;
 use rustc_hir::def_id::{CrateNum, LOCAL_CRATE};
@@ -344,7 +344,7 @@ pub struct CodegenContext<B: WriteBackendMethods> {
     /// how to call the compiler with the same arguments.
     pub expanded_args: Vec<String>,
 
-    /// Handler to use for diagnostics produced during codegen.
+    /// Emitter to use for diagnostics produced during codegen.
     pub diag_emitter: SharedEmitter,
     /// LLVM optimizations for which we want to print remarks.
     pub remark: Passes,
@@ -359,8 +359,8 @@ pub struct CodegenContext<B: WriteBackendMethods> {
 }
 
 impl<B: WriteBackendMethods> CodegenContext<B> {
-    pub fn create_diag_handler(&self) -> Handler {
-        Handler::with_emitter(Box::new(self.diag_emitter.clone()))
+    pub fn create_dcx(&self) -> DiagCtxt {
+        DiagCtxt::with_emitter(Box::new(self.diag_emitter.clone()))
     }
 
     pub fn config(&self, kind: ModuleKind) -> &ModuleConfig {
@@ -558,7 +558,7 @@ fn produce_final_output_artifacts(
             }
             if !sess.opts.cg.save_temps && !keep_numbered {
                 // The user just wants `foo.x`, not `foo.#module-name#.x`.
-                ensure_removed(sess.diagnostic(), &path);
+                ensure_removed(sess.dcx(), &path);
             }
         } else {
             let extension = crate_output
@@ -649,19 +649,19 @@ fn produce_final_output_artifacts(
         for module in compiled_modules.modules.iter() {
             if let Some(ref path) = module.object {
                 if !keep_numbered_objects {
-                    ensure_removed(sess.diagnostic(), path);
+                    ensure_removed(sess.dcx(), path);
                 }
             }
 
             if let Some(ref path) = module.dwarf_object {
                 if !keep_numbered_objects {
-                    ensure_removed(sess.diagnostic(), path);
+                    ensure_removed(sess.dcx(), path);
                 }
             }
 
             if let Some(ref path) = module.bytecode {
                 if !keep_numbered_bitcode {
-                    ensure_removed(sess.diagnostic(), path);
+                    ensure_removed(sess.dcx(), path);
                 }
             }
         }
@@ -669,7 +669,7 @@ fn produce_final_output_artifacts(
         if !user_wants_bitcode {
             if let Some(ref allocator_module) = compiled_modules.allocator_module {
                 if let Some(ref path) = allocator_module.bytecode {
-                    ensure_removed(sess.diagnostic(), path);
+                    ensure_removed(sess.dcx(), path);
                 }
             }
         }
@@ -825,10 +825,10 @@ fn execute_optimize_work_item<B: ExtraBackendMethods>(
     module: ModuleCodegen<B::Module>,
     module_config: &ModuleConfig,
 ) -> Result<WorkItemResult<B>, FatalError> {
-    let diag_handler = cgcx.create_diag_handler();
+    let dcx = cgcx.create_dcx();
 
     unsafe {
-        B::optimize(cgcx, &diag_handler, &module, module_config)?;
+        B::optimize(cgcx, &dcx, &module, module_config)?;
     }
 
     // After we've done the initial round of optimizations we need to
@@ -891,11 +891,7 @@ fn execute_copy_from_cache_work_item<B: ExtraBackendMethods>(
         match link_or_copy(&source_file, &output_path) {
             Ok(_) => Some(output_path),
             Err(error) => {
-                cgcx.create_diag_handler().emit_err(errors::CopyPathBuf {
-                    source_file,
-                    output_path,
-                    error,
-                });
+                cgcx.create_dcx().emit_err(errors::CopyPathBuf { source_file, output_path, error });
                 None
             }
         }
@@ -939,13 +935,13 @@ fn finish_intra_module_work<B: ExtraBackendMethods>(
     module: ModuleCodegen<B::Module>,
     module_config: &ModuleConfig,
 ) -> Result<WorkItemResult<B>, FatalError> {
-    let diag_handler = cgcx.create_diag_handler();
+    let dcx = cgcx.create_dcx();
 
     if !cgcx.opts.unstable_opts.combine_cgu
         || module.kind == ModuleKind::Metadata
         || module.kind == ModuleKind::Allocator
     {
-        let module = unsafe { B::codegen(cgcx, &diag_handler, module, module_config)? };
+        let module = unsafe { B::codegen(cgcx, &dcx, module, module_config)? };
         Ok(WorkItemResult::Finished(module))
     } else {
         Ok(WorkItemResult::NeedsLink(module))
@@ -1595,11 +1591,10 @@ fn start_executing_work<B: ExtraBackendMethods>(
         let needs_link = mem::take(&mut needs_link);
         if !needs_link.is_empty() {
             assert!(compiled_modules.is_empty());
-            let diag_handler = cgcx.create_diag_handler();
-            let module = B::run_link(&cgcx, &diag_handler, needs_link).map_err(|_| ())?;
+            let dcx = cgcx.create_dcx();
+            let module = B::run_link(&cgcx, &dcx, needs_link).map_err(|_| ())?;
             let module = unsafe {
-                B::codegen(&cgcx, &diag_handler, module, cgcx.config(ModuleKind::Regular))
-                    .map_err(|_| ())?
+                B::codegen(&cgcx, &dcx, module, cgcx.config(ModuleKind::Regular)).map_err(|_| ())?
             };
             compiled_modules.push(module);
         }
@@ -1842,13 +1837,13 @@ impl SharedEmitterMain {
 
             match message {
                 Ok(SharedEmitterMessage::Diagnostic(diag)) => {
-                    let handler = sess.diagnostic();
+                    let dcx = sess.dcx();
                     let mut d = rustc_errors::Diagnostic::new_with_messages(diag.lvl, diag.msg);
                     if let Some(code) = diag.code {
                         d.code(code);
                     }
                     d.replace_args(diag.args);
-                    handler.emit_diagnostic(d);
+                    dcx.emit_diagnostic(d);
                 }
                 Ok(SharedEmitterMessage::InlineAsmError(cookie, msg, level, source)) => {
                     let msg = msg.strip_prefix("error: ").unwrap_or(&msg).to_string();
diff --git a/compiler/rustc_codegen_ssa/src/codegen_attrs.rs b/compiler/rustc_codegen_ssa/src/codegen_attrs.rs
index 40a985cf255..e529956b1ba 100644
--- a/compiler/rustc_codegen_ssa/src/codegen_attrs.rs
+++ b/compiler/rustc_codegen_ssa/src/codegen_attrs.rs
@@ -386,7 +386,7 @@ fn codegen_fn_attrs(tcx: TyCtxt<'_>, did: LocalDefId) -> CodegenFnAttrs {
                                 [sym::arm, sym::a32] | [sym::arm, sym::t32] => {
                                     if !tcx.sess.target.has_thumb_interworking {
                                         struct_span_err!(
-                                            tcx.sess.diagnostic(),
+                                            tcx.sess.dcx(),
                                             attr.span,
                                             E0779,
                                             "target does not support `#[instruction_set]`"
@@ -403,7 +403,7 @@ fn codegen_fn_attrs(tcx: TyCtxt<'_>, did: LocalDefId) -> CodegenFnAttrs {
                                 }
                                 _ => {
                                     struct_span_err!(
-                                        tcx.sess.diagnostic(),
+                                        tcx.sess.dcx(),
                                         attr.span,
                                         E0779,
                                         "invalid instruction set specified",
@@ -415,7 +415,7 @@ fn codegen_fn_attrs(tcx: TyCtxt<'_>, did: LocalDefId) -> CodegenFnAttrs {
                         }
                         [] => {
                             struct_span_err!(
-                                tcx.sess.diagnostic(),
+                                tcx.sess.dcx(),
                                 attr.span,
                                 E0778,
                                 "`#[instruction_set]` requires an argument"
@@ -425,7 +425,7 @@ fn codegen_fn_attrs(tcx: TyCtxt<'_>, did: LocalDefId) -> CodegenFnAttrs {
                         }
                         _ => {
                             struct_span_err!(
-                                tcx.sess.diagnostic(),
+                                tcx.sess.dcx(),
                                 attr.span,
                                 E0779,
                                 "cannot specify more than one instruction set"
@@ -443,7 +443,7 @@ fn codegen_fn_attrs(tcx: TyCtxt<'_>, did: LocalDefId) -> CodegenFnAttrs {
                     rustc_attr::parse_alignment(&literal.kind)
                         .map_err(|msg| {
                             struct_span_err!(
-                                tcx.sess.diagnostic(),
+                                tcx.sess.dcx(),
                                 attr.span,
                                 E0589,
                                 "invalid `repr(align)` attribute: {}",
@@ -469,27 +469,17 @@ fn codegen_fn_attrs(tcx: TyCtxt<'_>, did: LocalDefId) -> CodegenFnAttrs {
             Some(MetaItemKind::List(ref items)) => {
                 inline_span = Some(attr.span);
                 if items.len() != 1 {
-                    struct_span_err!(
-                        tcx.sess.diagnostic(),
-                        attr.span,
-                        E0534,
-                        "expected one argument"
-                    )
-                    .emit();
+                    struct_span_err!(tcx.sess.dcx(), attr.span, E0534, "expected one argument")
+                        .emit();
                     InlineAttr::None
                 } else if list_contains_name(items, sym::always) {
                     InlineAttr::Always
                 } else if list_contains_name(items, sym::never) {
                     InlineAttr::Never
                 } else {
-                    struct_span_err!(
-                        tcx.sess.diagnostic(),
-                        items[0].span(),
-                        E0535,
-                        "invalid argument"
-                    )
-                    .help("valid inline arguments are `always` and `never`")
-                    .emit();
+                    struct_span_err!(tcx.sess.dcx(), items[0].span(), E0535, "invalid argument")
+                        .help("valid inline arguments are `always` and `never`")
+                        .emit();
 
                     InlineAttr::None
                 }
@@ -503,7 +493,7 @@ fn codegen_fn_attrs(tcx: TyCtxt<'_>, did: LocalDefId) -> CodegenFnAttrs {
         if !attr.has_name(sym::optimize) {
             return ia;
         }
-        let err = |sp, s| struct_span_err!(tcx.sess.diagnostic(), sp, E0722, "{}", s).emit();
+        let err = |sp, s| struct_span_err!(tcx.sess.dcx(), sp, E0722, "{}", s).emit();
         match attr.meta_kind() {
             Some(MetaItemKind::Word) => {
                 err(attr.span, "expected one argument");
@@ -578,7 +568,9 @@ fn codegen_fn_attrs(tcx: TyCtxt<'_>, did: LocalDefId) -> CodegenFnAttrs {
                     hir_id,
                     no_sanitize_span,
                     "`no_sanitize` will have no effect after inlining",
-                    |lint| lint.span_note(inline_span, "inlining requested here"),
+                    |lint| {
+                        lint.span_note(inline_span, "inlining requested here");
+                    },
                 )
             }
         }
diff --git a/compiler/rustc_codegen_ssa/src/errors.rs b/compiler/rustc_codegen_ssa/src/errors.rs
index ed6ac9f9c5d..668d39afbda 100644
--- a/compiler/rustc_codegen_ssa/src/errors.rs
+++ b/compiler/rustc_codegen_ssa/src/errors.rs
@@ -4,7 +4,7 @@ use crate::assert_module_sources::CguReuse;
 use crate::back::command::Command;
 use crate::fluent_generated as fluent;
 use rustc_errors::{
-    DiagnosticArgValue, DiagnosticBuilder, ErrorGuaranteed, Handler, IntoDiagnostic,
+    DiagCtxt, DiagnosticArgValue, DiagnosticBuilder, ErrorGuaranteed, IntoDiagnostic,
     IntoDiagnosticArg,
 };
 use rustc_macros::Diagnostic;
@@ -210,192 +210,191 @@ pub enum LinkRlibError {
 pub struct ThorinErrorWrapper(pub thorin::Error);
 
 impl IntoDiagnostic<'_> for ThorinErrorWrapper {
-    fn into_diagnostic(self, handler: &Handler) -> DiagnosticBuilder<'_, ErrorGuaranteed> {
+    fn into_diagnostic(self, dcx: &DiagCtxt) -> DiagnosticBuilder<'_, ErrorGuaranteed> {
         let mut diag;
         match self.0 {
             thorin::Error::ReadInput(_) => {
-                diag = handler.struct_err(fluent::codegen_ssa_thorin_read_input_failure);
+                diag = dcx.struct_err(fluent::codegen_ssa_thorin_read_input_failure);
                 diag
             }
             thorin::Error::ParseFileKind(_) => {
-                diag = handler.struct_err(fluent::codegen_ssa_thorin_parse_input_file_kind);
+                diag = dcx.struct_err(fluent::codegen_ssa_thorin_parse_input_file_kind);
                 diag
             }
             thorin::Error::ParseObjectFile(_) => {
-                diag = handler.struct_err(fluent::codegen_ssa_thorin_parse_input_object_file);
+                diag = dcx.struct_err(fluent::codegen_ssa_thorin_parse_input_object_file);
                 diag
             }
             thorin::Error::ParseArchiveFile(_) => {
-                diag = handler.struct_err(fluent::codegen_ssa_thorin_parse_input_archive_file);
+                diag = dcx.struct_err(fluent::codegen_ssa_thorin_parse_input_archive_file);
                 diag
             }
             thorin::Error::ParseArchiveMember(_) => {
-                diag = handler.struct_err(fluent::codegen_ssa_thorin_parse_archive_member);
+                diag = dcx.struct_err(fluent::codegen_ssa_thorin_parse_archive_member);
                 diag
             }
             thorin::Error::InvalidInputKind => {
-                diag = handler.struct_err(fluent::codegen_ssa_thorin_invalid_input_kind);
+                diag = dcx.struct_err(fluent::codegen_ssa_thorin_invalid_input_kind);
                 diag
             }
             thorin::Error::DecompressData(_) => {
-                diag = handler.struct_err(fluent::codegen_ssa_thorin_decompress_data);
+                diag = dcx.struct_err(fluent::codegen_ssa_thorin_decompress_data);
                 diag
             }
             thorin::Error::NamelessSection(_, offset) => {
-                diag = handler.struct_err(fluent::codegen_ssa_thorin_section_without_name);
+                diag = dcx.struct_err(fluent::codegen_ssa_thorin_section_without_name);
                 diag.set_arg("offset", format!("0x{offset:08x}"));
                 diag
             }
             thorin::Error::RelocationWithInvalidSymbol(section, offset) => {
-                diag =
-                    handler.struct_err(fluent::codegen_ssa_thorin_relocation_with_invalid_symbol);
+                diag = dcx.struct_err(fluent::codegen_ssa_thorin_relocation_with_invalid_symbol);
                 diag.set_arg("section", section);
                 diag.set_arg("offset", format!("0x{offset:08x}"));
                 diag
             }
             thorin::Error::MultipleRelocations(section, offset) => {
-                diag = handler.struct_err(fluent::codegen_ssa_thorin_multiple_relocations);
+                diag = dcx.struct_err(fluent::codegen_ssa_thorin_multiple_relocations);
                 diag.set_arg("section", section);
                 diag.set_arg("offset", format!("0x{offset:08x}"));
                 diag
             }
             thorin::Error::UnsupportedRelocation(section, offset) => {
-                diag = handler.struct_err(fluent::codegen_ssa_thorin_unsupported_relocation);
+                diag = dcx.struct_err(fluent::codegen_ssa_thorin_unsupported_relocation);
                 diag.set_arg("section", section);
                 diag.set_arg("offset", format!("0x{offset:08x}"));
                 diag
             }
             thorin::Error::MissingDwoName(id) => {
-                diag = handler.struct_err(fluent::codegen_ssa_thorin_missing_dwo_name);
+                diag = dcx.struct_err(fluent::codegen_ssa_thorin_missing_dwo_name);
                 diag.set_arg("id", format!("0x{id:08x}"));
                 diag
             }
             thorin::Error::NoCompilationUnits => {
-                diag = handler.struct_err(fluent::codegen_ssa_thorin_no_compilation_units);
+                diag = dcx.struct_err(fluent::codegen_ssa_thorin_no_compilation_units);
                 diag
             }
             thorin::Error::NoDie => {
-                diag = handler.struct_err(fluent::codegen_ssa_thorin_no_die);
+                diag = dcx.struct_err(fluent::codegen_ssa_thorin_no_die);
                 diag
             }
             thorin::Error::TopLevelDieNotUnit => {
-                diag = handler.struct_err(fluent::codegen_ssa_thorin_top_level_die_not_unit);
+                diag = dcx.struct_err(fluent::codegen_ssa_thorin_top_level_die_not_unit);
                 diag
             }
             thorin::Error::MissingRequiredSection(section) => {
-                diag = handler.struct_err(fluent::codegen_ssa_thorin_missing_required_section);
+                diag = dcx.struct_err(fluent::codegen_ssa_thorin_missing_required_section);
                 diag.set_arg("section", section);
                 diag
             }
             thorin::Error::ParseUnitAbbreviations(_) => {
-                diag = handler.struct_err(fluent::codegen_ssa_thorin_parse_unit_abbreviations);
+                diag = dcx.struct_err(fluent::codegen_ssa_thorin_parse_unit_abbreviations);
                 diag
             }
             thorin::Error::ParseUnitAttribute(_) => {
-                diag = handler.struct_err(fluent::codegen_ssa_thorin_parse_unit_attribute);
+                diag = dcx.struct_err(fluent::codegen_ssa_thorin_parse_unit_attribute);
                 diag
             }
             thorin::Error::ParseUnitHeader(_) => {
-                diag = handler.struct_err(fluent::codegen_ssa_thorin_parse_unit_header);
+                diag = dcx.struct_err(fluent::codegen_ssa_thorin_parse_unit_header);
                 diag
             }
             thorin::Error::ParseUnit(_) => {
-                diag = handler.struct_err(fluent::codegen_ssa_thorin_parse_unit);
+                diag = dcx.struct_err(fluent::codegen_ssa_thorin_parse_unit);
                 diag
             }
             thorin::Error::IncompatibleIndexVersion(section, format, actual) => {
-                diag = handler.struct_err(fluent::codegen_ssa_thorin_incompatible_index_version);
+                diag = dcx.struct_err(fluent::codegen_ssa_thorin_incompatible_index_version);
                 diag.set_arg("section", section);
                 diag.set_arg("actual", actual);
                 diag.set_arg("format", format);
                 diag
             }
             thorin::Error::OffsetAtIndex(_, index) => {
-                diag = handler.struct_err(fluent::codegen_ssa_thorin_offset_at_index);
+                diag = dcx.struct_err(fluent::codegen_ssa_thorin_offset_at_index);
                 diag.set_arg("index", index);
                 diag
             }
             thorin::Error::StrAtOffset(_, offset) => {
-                diag = handler.struct_err(fluent::codegen_ssa_thorin_str_at_offset);
+                diag = dcx.struct_err(fluent::codegen_ssa_thorin_str_at_offset);
                 diag.set_arg("offset", format!("0x{offset:08x}"));
                 diag
             }
             thorin::Error::ParseIndex(_, section) => {
-                diag = handler.struct_err(fluent::codegen_ssa_thorin_parse_index);
+                diag = dcx.struct_err(fluent::codegen_ssa_thorin_parse_index);
                 diag.set_arg("section", section);
                 diag
             }
             thorin::Error::UnitNotInIndex(unit) => {
-                diag = handler.struct_err(fluent::codegen_ssa_thorin_unit_not_in_index);
+                diag = dcx.struct_err(fluent::codegen_ssa_thorin_unit_not_in_index);
                 diag.set_arg("unit", format!("0x{unit:08x}"));
                 diag
             }
             thorin::Error::RowNotInIndex(_, row) => {
-                diag = handler.struct_err(fluent::codegen_ssa_thorin_row_not_in_index);
+                diag = dcx.struct_err(fluent::codegen_ssa_thorin_row_not_in_index);
                 diag.set_arg("row", row);
                 diag
             }
             thorin::Error::SectionNotInRow => {
-                diag = handler.struct_err(fluent::codegen_ssa_thorin_section_not_in_row);
+                diag = dcx.struct_err(fluent::codegen_ssa_thorin_section_not_in_row);
                 diag
             }
             thorin::Error::EmptyUnit(unit) => {
-                diag = handler.struct_err(fluent::codegen_ssa_thorin_empty_unit);
+                diag = dcx.struct_err(fluent::codegen_ssa_thorin_empty_unit);
                 diag.set_arg("unit", format!("0x{unit:08x}"));
                 diag
             }
             thorin::Error::MultipleDebugInfoSection => {
-                diag = handler.struct_err(fluent::codegen_ssa_thorin_multiple_debug_info_section);
+                diag = dcx.struct_err(fluent::codegen_ssa_thorin_multiple_debug_info_section);
                 diag
             }
             thorin::Error::MultipleDebugTypesSection => {
-                diag = handler.struct_err(fluent::codegen_ssa_thorin_multiple_debug_types_section);
+                diag = dcx.struct_err(fluent::codegen_ssa_thorin_multiple_debug_types_section);
                 diag
             }
             thorin::Error::NotSplitUnit => {
-                diag = handler.struct_err(fluent::codegen_ssa_thorin_not_split_unit);
+                diag = dcx.struct_err(fluent::codegen_ssa_thorin_not_split_unit);
                 diag
             }
             thorin::Error::DuplicateUnit(unit) => {
-                diag = handler.struct_err(fluent::codegen_ssa_thorin_duplicate_unit);
+                diag = dcx.struct_err(fluent::codegen_ssa_thorin_duplicate_unit);
                 diag.set_arg("unit", format!("0x{unit:08x}"));
                 diag
             }
             thorin::Error::MissingReferencedUnit(unit) => {
-                diag = handler.struct_err(fluent::codegen_ssa_thorin_missing_referenced_unit);
+                diag = dcx.struct_err(fluent::codegen_ssa_thorin_missing_referenced_unit);
                 diag.set_arg("unit", format!("0x{unit:08x}"));
                 diag
             }
             thorin::Error::NoOutputObjectCreated => {
-                diag = handler.struct_err(fluent::codegen_ssa_thorin_not_output_object_created);
+                diag = dcx.struct_err(fluent::codegen_ssa_thorin_not_output_object_created);
                 diag
             }
             thorin::Error::MixedInputEncodings => {
-                diag = handler.struct_err(fluent::codegen_ssa_thorin_mixed_input_encodings);
+                diag = dcx.struct_err(fluent::codegen_ssa_thorin_mixed_input_encodings);
                 diag
             }
             thorin::Error::Io(e) => {
-                diag = handler.struct_err(fluent::codegen_ssa_thorin_io);
+                diag = dcx.struct_err(fluent::codegen_ssa_thorin_io);
                 diag.set_arg("error", format!("{e}"));
                 diag
             }
             thorin::Error::ObjectRead(e) => {
-                diag = handler.struct_err(fluent::codegen_ssa_thorin_object_read);
+                diag = dcx.struct_err(fluent::codegen_ssa_thorin_object_read);
                 diag.set_arg("error", format!("{e}"));
                 diag
             }
             thorin::Error::ObjectWrite(e) => {
-                diag = handler.struct_err(fluent::codegen_ssa_thorin_object_write);
+                diag = dcx.struct_err(fluent::codegen_ssa_thorin_object_write);
                 diag.set_arg("error", format!("{e}"));
                 diag
             }
             thorin::Error::GimliRead(e) => {
-                diag = handler.struct_err(fluent::codegen_ssa_thorin_gimli_read);
+                diag = dcx.struct_err(fluent::codegen_ssa_thorin_gimli_read);
                 diag.set_arg("error", format!("{e}"));
                 diag
             }
             thorin::Error::GimliWrite(e) => {
-                diag = handler.struct_err(fluent::codegen_ssa_thorin_gimli_write);
+                diag = dcx.struct_err(fluent::codegen_ssa_thorin_gimli_write);
                 diag.set_arg("error", format!("{e}"));
                 diag
             }
@@ -412,8 +411,8 @@ pub struct LinkingFailed<'a> {
 }
 
 impl IntoDiagnostic<'_> for LinkingFailed<'_> {
-    fn into_diagnostic(self, handler: &Handler) -> DiagnosticBuilder<'_, ErrorGuaranteed> {
-        let mut diag = handler.struct_err(fluent::codegen_ssa_linking_failed);
+    fn into_diagnostic(self, dcx: &DiagCtxt) -> DiagnosticBuilder<'_, ErrorGuaranteed> {
+        let mut diag = dcx.struct_err(fluent::codegen_ssa_linking_failed);
         diag.set_arg("linker_path", format!("{}", self.linker_path.display()));
         diag.set_arg("exit_status", format!("{}", self.exit_status));
 
diff --git a/compiler/rustc_codegen_ssa/src/traits/write.rs b/compiler/rustc_codegen_ssa/src/traits/write.rs
index ecf5095d8a3..048540894ac 100644
--- a/compiler/rustc_codegen_ssa/src/traits/write.rs
+++ b/compiler/rustc_codegen_ssa/src/traits/write.rs
@@ -2,7 +2,7 @@ use crate::back::lto::{LtoModuleCodegen, SerializedModule, ThinModule};
 use crate::back::write::{CodegenContext, FatLtoInput, ModuleConfig};
 use crate::{CompiledModule, ModuleCodegen};
 
-use rustc_errors::{FatalError, Handler};
+use rustc_errors::{DiagCtxt, FatalError};
 use rustc_middle::dep_graph::WorkProduct;
 
 pub trait WriteBackendMethods: 'static + Sized + Clone {
@@ -16,7 +16,7 @@ pub trait WriteBackendMethods: 'static + Sized + Clone {
     /// Merge all modules into main_module and returning it
     fn run_link(
         cgcx: &CodegenContext<Self>,
-        diag_handler: &Handler,
+        dcx: &DiagCtxt,
         modules: Vec<ModuleCodegen<Self::Module>>,
     ) -> Result<ModuleCodegen<Self::Module>, FatalError>;
     /// Performs fat LTO by merging all modules into a single one and returning it
@@ -38,7 +38,7 @@ pub trait WriteBackendMethods: 'static + Sized + Clone {
     fn print_statistics(&self);
     unsafe fn optimize(
         cgcx: &CodegenContext<Self>,
-        diag_handler: &Handler,
+        dcx: &DiagCtxt,
         module: &ModuleCodegen<Self::Module>,
         config: &ModuleConfig,
     ) -> Result<(), FatalError>;
@@ -52,7 +52,7 @@ pub trait WriteBackendMethods: 'static + Sized + Clone {
     ) -> Result<ModuleCodegen<Self::Module>, FatalError>;
     unsafe fn codegen(
         cgcx: &CodegenContext<Self>,
-        diag_handler: &Handler,
+        dcx: &DiagCtxt,
         module: ModuleCodegen<Self::Module>,
         config: &ModuleConfig,
     ) -> Result<CompiledModule, FatalError>;